Collapsible mining head



Feb. l2, 1963 c. T. GovlN 3,077,235

coLLAPsIBLE MINING HEAD Filed Aug. 3, 1960 4 Sheets-Sheet 2 l '5 JNVENToR. EL? CHARLES Z'Go wu HIJ A Trau/EY Feb. l2, 1963 c. T. GovlN 3,077,235

COLLAPSIBLE MINING HEAD Filed Aug. 3, 1960 4 Sheets-Sheet 5 INVENTOR. CHA/@L E5 TG@ vw Feb. 12, 1963 C, T, GQVlN COLLAPSIBLE MINING HEAD 4 Sheets-Sheet 4 Filed Aug. 3, 1960 om S, A Q www mw Nm Nm mm mm Wm. HH.

H15 A r rolex/5 Y ilnited States @stent @bien 3,677,235 CGILLAPSEBLE MENWG HEAD Charles T. Gavin, Saiem, hio, assigner to The Salem Tool Company, Salem, (Ohio, a corporation of @trio Filed Aug. 3, 1960. Ser. No. 47,292 18 Claims. (Cl. 17E-23:3)

This invention relates generally to a mining head 'and more particularly to a rotary mining head that is collapsible to withdraw it through an opening smaller than that which it cuts when expanded.

The collapsible mining head comprising this invention provides a collapsible structure permitting it to be readily withdrawn from the hole it has drilled. This is particularly advantageous when yboring a hole to receive casing and the hole cut must be larger than the outside dimension of casing to follow or shove the casing into the hole behind the cutter and permit the mining head to be collapsed and retracted through the casing for changing bits and for other purposes. The hole bored may be made by a single or plural mining heads followed by single or multiple casing joined to form a single opening.

The use of a collapsible mining head to bore a single hole into which a casing is shoved in following the head has many applications such as inserting a culvert under a road or railroad bed or property where the surface cannot be disturbed to dig a pitch. The casing lined hole may be used for other purposes than for conducting liquid. Frequently it is necessary to conduct different liquids through the same culvert or conduit in which case terra cotta and metal piping may extend through the casing. Such holes are generally horizontal or slope in one direction or the other. Such holes must be accurately made which accuracy is obtained by guiding the tube which carries the augers that supports the mining heads. Thus a properly guided tube following the mining heads in turn guides the mining heads through supporting the augers. The same is true of a vertical hole for a well, a line pole, a piling. By drilling these holes and following the mining head with a casing one may penetrate soft material and continue drilling without a cave-in. The change in the material drilled will require different heads. The mining head for sand is not good for jumbo or marsh, nor for hard rock. Thus the collapsible mining head permits the withdrawal of the head through the casing to change the pilot head and bits on the collapsible arms of which there may be a single arm or a plurality on one mining head.

The collapsible mining head comprising this invention is provided with one or more bit supporting arms pivoted to a body that also carries the pilot head and is slidaole axially on the rotary shaft without relative rotary movement. This arm is also pivotally connected to a link the other end of which i-s pivoted to the rotary shaft member. Thus when the pilot head is against the dirt and the shaft is moved forwardly toward the pilot head, the link extends the arm laterally and thus expands the head. When the shaft is retracted, the link is drawn back drawing in the arm to collapse this portion of the head. When the head is muddy and is followed by a casing, the outer part of the link will strike the casing and cause the shaft to pull the link inwardly and thereby collapse the head.

To increase the size of holes and casing, one need only replace the arms to make them longer or increase the length of the arms and their links or change the location of their pivotal points on the same body.

The body of the head has a shoulder to engage the shaft for transmitting force to feed the drill into the earth. At this position the link is moved beyond dead center and the arm cannot collapse.

It is preferable to cut very little clearance for the casing. In this way the hole may be drilled very straight and the mining head well centered.

aan

The arms may be pivoted between parallel shoulders on the body to transmit digging forces from the body to the arms and their bits without over-loading the pivotal connection.

Other objects and advantages appear hereinafter in the following description and claims.

The accompanying drawings show for the purpose of exempliiication without limiting this invention or the claims thereto, certain practical embodiments illustrating the principles of this invention wherein:

FIG. l is -a view partly in section of an expanded mining head in a horizontal hole.

FIG. 2 is a View partly in section showing the head starting to collapse in a horizontal hole.

FIG. 3 is a view partly in section ofthe head completely collapsed and withdrawn in a horizontal tube.

FIG. 4 is a View in end elevation of the mining head having four arms and with the pilot head removed.

FIG. 5 is a view in side elevation of another mining head structure having two arms.

FIG. 6 is a perspective View of another panded head.

FIG. 7 is a perspective View showing the head of FIG. 6 starting to collapse.

FIG. 8 is a perspective view showing the head of FIG. 6 collapsed and Withdrawn.

FIG. 9 is a view partly in section of another form of au expanded mining head in a vertical hole.

FlG. l0 is a view partly in section showing the head of FIG. 9 starting to collapse.

FIG. ll is a view partly in section of the head of FIG. 9 completely collapsed and withdrawn into the casing.

Referring to FIGS. l to 3 the mining head l is made up of the slide or body member 2, the pilot bit 3 and the pilot head d. The body or slide 2 is mounted on the nonround stem or extension 5 that is slidable within the complementary bore or guide means 6 of the shaft member '7 which is in this instance a helical auger section 3 and is in turn provided with a nonround pin member 1t) slidable within the mating socket 1l of the next consecutive auger section l2 joined at mating shoulders indicated at i3. Said auger section 8 functions to hold said shaft centered in said casing as well as to withdraw the mined material out of the casing.

The body or slide 2 is provided with a shoulder 14 which engages the shoulder 1S on the end of the auger section 8 transmitting axial force in operating the mining head 1.

The pilot head 4 is also provided with a nonround stem lo that is secured in a mating socket i7 in the body 2. The outer end of the pilot head t is likewise provided with a nonround socket 1S to receive the stem 2i) of the pilot bit 3. Each of the sections of the mining head and the body are provided with removable cutting bits indicated at 2l and the central pilot bit 3 is provided with a central cutting bit 22.

As shown in FIG. l the mining head 1 is expanded so that the cutting bits 2l on the body and the cutting bits of the pilot bit and head sections 3 and i are all in engagement with the material to be bored or mined and are in the process of cutting the hole. Each section of the mining head cuts its own diameter as illustrated by the different bores 23, 24. and Z5.

The body or slide 2 is form of an exprovided with a plurality of pairs `of radially disposed parallel shoulders 2o and Z7 between which is movably mounted the bit carrying cutting arm members 23 of which there are two employed in FlGS. l to 3 inclusive, however, there may be one or more than two arms provided in a mining head.

The bit carrying cutting arms 28 are pivoted at 36 to the spaced shoulders 26 and 27; the pivot pin Sil being adjacent the inner end of the bit carrying cutting arms 28.

The outer-end of the bit carrying cutting arm 2Sis provided with a pivot member 31 to secure the connected double or parallel link member 32 to the arms as shown in FIG. 7, said links 32 are made dual so as to embrace the opposite faces of the cutting arms 23 and the pivot support means 33. The shaftmember 7 is provided with a pair of oppositely disposed pivot support means 33 to which the inner ends of the parallel links 32 are pivoted asindicated at 34..

When the mining head is extended by forcing of the shaft 7 inwardly the pilotv sections 3 and 4: engage .the mining. wall facing the pivot support means 33 and the shaft 7 .moves forward thereby forcing the parallel links 32 laterally outward to cause the arms 23 to likewise swing outwardly and permit their bits 2l. to cut the bore 25. When the pivots 34 connected to the parallel links 32 have -passed beyond the transverseplane of the pivot members 31, the links 32 are said to have passed their dead center and thus lock the bit carrying cutting arms 28 in their outermost position and any axial force impressed on the mining head through the shaft 7 prevents the arms from collapsing causing their bits 21 to mine the bore 25.

lWhen the shoulders 14 and 15 are in engagement and the, location of the pivotal points of thearms 23' and links 32 are chosen to prevent the pivot points 34 from passing the transverse plane of the pivots 31 then the links 32Y would assume the principal part of the thrust load on the bits 21. Such a condition would be assumed if the shoulder 14 of thelbodyv2 was extended to engage lthe shoulder 15 in the position illustrated in FIGS. 2, 7 or l0.

' At this position the shoulder 11ion the mining head engages the shoulder 15 on the end of the shaft? for the purpose of transmitting the axial cutting forces to the mining head and at the same time the nonround stem or extension in its complementary bore 6 transmits the rotary cutting forces from the shaft 7 to the mining head1.

When the mining head is expanded as-shown the outer ends of the parallel links 32 extend outwardly beyond the. casing 35, the bore 36 of which provides an adequate clearance for the auger sections S and 12 and thus provide a bearing or guide surface for the mining head ll. As axial forces are applied to the rotary shaft '7 to feed the mining head 1 in boring or mining a hole a forward position is also applied by the mining machine to move the casing 35 forwardly toward but just behind the mining head 1. The lengths of the auger sections 8 and 12 are determined so as to maintain the mining head in front of the casing 35 a distance just sufficient to provide a desired clearance and to prevent any interference of the mined material from Aentering the casing and being withdrawn rearwardly by the action of the auger sections.

It is preferable to employ a mining head that cuts just sufficient clearance for the casing 35 so as to insure accurate guiding of the mining head in leading the casing throughthe mined material.

The sections 3 and 4 of the pilot bit which are xed always have clearance to pass through the bore 36 of the casing 35 `and the design or character of these pilot bit sections are selected to suit the soilV or conditions of the material being mined.

As shown in FlGS. 2, 7 and l0 let it be assumed that it is desired to withdraw the mining head from the casing 35 which is done by merely withdrawing the shaft '7 that carries the auger flights as indicated at 8 and 12. Since each consecutive auger section is secured to each other by means of the pins 37 the auger sections will be moved rearwardly. They of course may be rotated simultaneously to draw the material mined back through the bore of the casing 35. However, the mining head 1 begins to leave the mining face and the shoulders 14 and 15 part due to relative longitudinal movement therebetween exposing a portion of the stem section or extension 5 starting to slide relatively outwardly in the complementary bore or guide means 6 or contra vif the bore 6 is withdrawn from the stem 5. As the mining head 1 is drawn back toward the end of the casing 3S the inner ends of the parallel links 32 are drawn rearwardly so that their pivots 34 are no longer over dead center with respect to the pivots 31 then the link will abut the end of the casing as illustrated in FIGS. 2, 6 and 9 and arrest further rearward movement of the mining head until the shaft 7 is further withdrawn to completely collapse the mining head. Thus the end of the casing 35 forms an abutment and by withdrawing the arms 23 inwardly so that their outermost bits 21 will readily pass within the bore 36 of the casing 35 as shownlin FIGS. 3, 8 and ll. Thus the miningihe'ad is completely collapsed and may bedrawn out of the casing 35 tov permit the bits orfparts of the pilot bit sections or the whole head for that matter to be changed to suit 'the mining conditions. The casing 35 of course remains'in the hole and is in proper position for the re-entry'of the mining head 1 to complete the boring operation.

As sho-wn in FiGS. l to 3 the structure cuts a hole for the'twenty-four inch OD. casing 3S and the arms 2.8' are provided withva series of five bits each 21 and theparallel links 32 as well as the bit carrying cutting arms 28 which are materially longer than the lcorresponding parts as shown in FlGS. 5 to 8, which structure cuts a hole for the eighteeny inch GD. casing A35.

ln NGS. 6 to 8, the bit Ycarrying cutting arms 28 are provided with three bits 21 and the` parallel shoulders 26 and 27 have approximately the same clearance with the bore 36 of the casing 3S as do the auger sections 3 and 12.

lt will also be noted that only one pilot head section 3 is requirerlin the collapsible mining head 1 as shown in FIGS. 5 to -ll owing to the fact that it is of different size.v

in the structure shown in FiGS. 9 to ll for cutting holes to receive the twelve inch LD casing '35, the bit carrying cutting arms 2S have only two bits 21 and'areniaterially shorter-than those of the previously described structures. In this-structure, it is also vshown that the abutments y33 are block sections that extend between the shoulders 4111i and v15 of the mining head '1 and shaft section 'ln' other words, ythe length ofthe parallel links 32 isfgrea'ter than that Vof the desired length of the slid'able'stem 5` and it isltherefore'necessary to employ the 'abutments33 as pressure transmitting blocks for the axial forces delivered from the rotary shaft 7 `to the mining head 1.7 YIt will also be noted that the structures as illustrated in FIGS. 6 and 9'show the pivot points 34 being over dead center with relation to the pivot points 31 at opposite ends of the parallel links 32. n

in the structure as illustrated in FIGS. 9 to l'l the mining head 1 may be materially smaller in diamter than the bore 36 of the casing 35 and will readily pass upwardly therethrough as shown in FG. 1l.

I claim:

l. A collapsible rotary cutting head comprising '-a rotary shaft having a bore in its outer end, pivot means carried on said shaft, a slide having a pin slidable in said bore to provide relative axial movement for said slide on said rotary shaft, an outwardly extending cutting Yarm having one end pivotally connected to said slide, a link pivoted to said cutting arm and said pivot means respectively, the length between the pivots of said link being selected to extend saidrcutting arm in cutting position when said link is extended laterally outward from said shaft to position said link past dead center whenl said slide is at its innermost position of its relative movement toward said pivot means.

2. The collapsible rotary cutting head of claim 1 characterized by a thrust shoulder on said shaft to limit the innermost relative movement of said slide toward said shaft and thrust shoulder to transmit cutting forces from said shaft and slide to said cutting arm.

3. The collapsible rotary cutting head of Ycla-iin 1 charyacterized'by a pilot bit carried by said slide.

4. The collapsible rotary cutting head of claim 3 ch'aracterized in that said pilot bit comprises two sections, one section mounted on said slide to cut a large hole and a second section mounted on said rst section to cut a smaller opening than that cut by said iirst section rand both sections cutting an opening smaller than that cut by said extensible cutting arm.

5. A hole boring mechanism consisting of a casing the outer end of which constitutes 4an abutment, a rotary boring shaft extending through said casing and carrying a cutting head, means to support said shaft near the center of said casing, pivot means on the outer end of said shaft, guide means on the outer end of said shaft, a slide to support the cutting head, an extension on said slide slidable in said guide means to provide relative axial movement for said slide on said rotary shaft and to transmit rotary boring forces for the cutting head on said slide, a cutting arm having one end pivotally connected to said slide to permit it to extend later-aliy outwardly beyond the abutment of said casing in cutting position, .a link pivoted to said cutting arm and to said pivot means respectively, a stop on said shaft to limit the inner axial movement of said slide and locate said link laterally outward to hold said arm in extended cutting position beyond the abutment of said casing with said pivot means positioned axially outwardly beyond the pivotal connection between said link and arm to lock said link past dead center, the retraction of said shaft into said casing permitting said link to engage the outer abutment end of said casing to puil said pivot means axially inwardly past the pivotal connection between said link and cutting arm to unlock and withdraw said cutting arm from cutting position and into said casing.

6. A coilapsible rotary cutting head comprising a rotary shaft having `a bore in its outer end, pivot means carried on said shaft, a slide having la pin slidable in said bore to provide relative axial movement for said slide on said shaft, a cutting arm having one end pivotally connected to said slide, .a link pivoted to said cutting arm and to said pivot means respectively, said cutting arm is in cutting position when said link is extended outward from said shaft and said siide and pin are located in their innermost positions with respect to the bore in said shaft.

7. The collapsible cutting head of claim 6 characterized by a shoulder on said shaft Ito limit the position of said slide and locate said link in its outermost position.

S. The collapsible cutting head of claim 7 characterized in that said shoulder stops said slide to position said pivot means beyond the pivotal connection between said link and arm to Vlock said link in past dead center position.

9. The structure of claim 6 characterized in that said slide carries a plurality of pivoted cutting arms and each is provided with a pivoted link connected to a plurality of pivot means on said shaft, said arms being spaced circumferentially on said slide and said pivot means retracting said arms simultaneously when said shaft is drawn rearwardly.

10. 'The structure of claim 6 characterized by spaced shoulders mounted on said slide and between which said cutting arm is pivoted, said cutting arm retracted between said shoulders when said shaft is drawn rearwardly.

11. The structure of claim 6 characterized in that said link includes two spaced parallel link members interconnected intermediate their pivoted ends and embracing said cutting arm at one end and said shaft pivot means at the other.

12. The structure of claim 6 characterized in that the stem of said slide and the bore of said shaft have mating polygonal sliding surfaces therebetween.

13. The structure of claim 6 characterized in that said cutting arm and said link are replaceable by a cutting arm and link of different size to change the dimension of the hole.

14. The structure of claim 6 characterized in that said slide has a central polygonal sliding bore and a piiot bit means having a mating stem removably mounted in said bore.

15. The structure of claim 6 characterized by a tube inserted over said shaft and having an outer diameter smaller than the hole cut by said rotary cutting arms, an abutment on said tube to engage said link when retracting said shaft to collapse said cutting arm.

16. The structure of claim 15 characterized by a radial member on said shaft to support the sai-me centrally of said tube -and thus guide said rotary cutting head to engage said abutment.

17. The structure of claim 16 characterized in that said radial member is a spiral auger on said shaft.

18. The structure of claim 17 characterized in that said auger extends commensurate with said pivot means on said shaft.

References Cited in the le of this patent UNITED STATES PATENTS 2,675,213 Poole et al. Apr. 13, 1954 2,745,656 Smith May 15, 1956 2,750,176 Cartlidge June 12, 1956 2,772,869 Tracy Dec. 4, 1956 2,910,274 Scott Oct. 27, 1959 

6. A COLLAPSIBLE ROTARY CUTTING HEAD COMPRISING A ROTARY SHAFT HAVING A BORE IN ITS OUTER END, PIVOT MEANS CARRIED ON SAID SHAFT, A SLIDE HAVING A PIN SLIDABLE IN SAID BORE TO PROVIDE RELATIVE AXIAL MOVEMENT FOR SAID SLIDE ON SAID SHAFT, A CUTTING ARM HAVING ONE END PIVOTALLY CONNECTED TO SAID SLIDE, A LINK PIVOTED TO SAID CUTTING ARM AND TO SAID 